« AP » is the « signature » of Anita Porchet, one of the best (if not the best) independant « émailleuse » in the world, who is working for Patek Philippe 😉
“regular production” and New York LE) were also made by AP, although no initials were put on them. Personally I prefer the dial to have AP on it as it represents a meaningful partnership between two TOP “brands”😃